Gray anthraquinone dye.



UNITED sTnrns-rgarnur ,ouuicn.

WALTER MIEG, Oi 'ELBERFELD, GERMANY, ASSIGNOR T0 FAR-BENFAB RIKEN VORM.FRIEDR. BAYER 8c 00., OF ELBERF'EIJD, GERMANY, A CORPORATION OF GERMANY.

No Drawing.

To all whom it"ma'y concern:

Be it known that I, WALTER Mme, doctor of philosophy, chemist, citizenof the German Empire, residing at Elberfeld, Germany, have invented newand useful Intprovements in Gray Anthraquinone Dyes, of which thefollowing is a specification.

I have found that alpha-alpha-anthrimids which are obtained bycondensing alphaaminoanthraquinones with chloroanthraquinones yield uponconversion intu new nitrocompounds on treatment with reducing agentsnewdyestuffs capable of forming vats from which unmordanted cotton can bedyed in fast grayfshades. 'The new products are dark powders, colublewith diificulty in quinand form vats with hydrosulfiteandcaustic sodalye, which vats dye unmordanted cotton gray shades.

10 parts of alpha-alpha-dianthrimid (obtainable fromalpha-aminoanthraquinone and alpha-chloroanthraquinone) are intro ducedlnto 80 parts of a 95 per cent. nitric acid which has to be continuallystirred; The imid enters first in solution while the temperatureof theimxture rises,'but after a short time the nitro product separates in theshape of orange crystals which are filtered off, washedwith cold waterand-dried. In-

stead of HNO other nitrating agents may be used. The new nitro productthus obtained forms orange colored crystals, rather easily soluble withorange color on warming in organic solvents of high boiling point, suchas nitro benzol and anilin; on warming with pyridine a compound isformed which crystallizes out, very diflicultly soluble in concentratedsulfuric acid but soluble in fuming acid 015 30% SO -with olive greencolor, furnishing on boiling with strong causticsoda lye'a darkcoloredsolution from which the nitro-compound cannot be. separated anymore.

A solution of 'parts of sodium sulfid (Na S) is added to 20 parts ofthenitro-coinpound of alpha alpha-dianthrimid suspended in water and theresulting mixture is heated to boiling. After boiling for aSpecification of Letters Patent.

- short time reducing agents Patented May 31, 1910.

Application f led August 19, 1909. Serial No. 513,652. 7

the dyestufl is filtered oil and Washed with hot water. It is agreenishblack crystalline powder scarcely soluble in organic solvents.Its solution in concen-. trated sulfuric acid is een, which color turnsviolet by the addition of formic aldehyde. It is soluble in boilingquinolin with a green color.' On treatment with alkaline olive-brown vatcotton can be dyed in fast greenish-gray shades. The process is carriedout in an analogous manner on starting from other alpha-alpha-anthrimidse. g. from product obtained by condensing o'ne'molecule of 1.5- or1.8-diaminoanthraquinone with two molecul sofalpha-chloro-anthraquinone. The ior resulting from these anthrimidsdyecotton grayish shades. I

I claiin: '1. The herein described vat dyes, obtain-' able by preparingnitroalpha-alpha-anthri- 'mids and treating. the nitro-compounds thusthe new product forms an from which unmordanted produced with reducingagents, which are after being ders soluble with difiiculty inquinolins'and forrni'r'ig vats with hydrosulfiteand caustic dried andpulveri'zed dark pow- I soda lye, which vats dye unmordanted cotton grayshades, substantially as described. 2. The hereindescribed'vat dye,

able by nitrating alpha-'alpha-dianthrimid I and reducin the nitro-cornound' thus produced, whic' dye is after 'eing dried and.

pulverized soluble inorganic so1vents,-soluble in concentrated sulfuricacid with a'green color which turns violet by the addition of formic.aldehyde'and forming an olive-brown vat with hydrcsulfiteand causticsoda lye, .which vat dyes unmordanted cotton fast greenishgray shades,substantially as-described. In testimony whereof Ihave hereunto set.

obtaina greenish black powder scarcely my hand in the presence of twosubscribing 1 witnesses WALTER 'MIEG; [1,. s]

\Vitnesses:

O'r'roKomo, WILLY KLEIN.

